Optimal scheduling of a multiproduct batch chemical plant with preemptive changeover tasks

•Revisiting a real-life challenging problem yet to be solved to optimality.•Short-term scheduling over a time horizon with weekend breaks and a plant shutdown.•Preemptive scheduling of changeover tasks key element of optimization.•New modeling tricks for the discrete-time RTN formulation.•5% cost savings compared to an enumeration algorithm with heuristic rules.